xfs: support in-memory btrees

Adapt the generic btree cursor code to be able to create a btree whose
buffers come from a (presumably in-memory) buftarg with a header block
that's specific to in-memory btrees.  We'll connect this to other parts
of online scrub in the next patches.

Note that in-memory btrees always have a block size matching the system
memory page size for efficiency reasons.  There are also a few things we
need to do to finalize a btree update; that's covered in the next patch.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 7 insertions, 0 deletions

diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index bacd67cc8ced..f93374278aa1 100644
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -112,6 +112,7 @@ static inline enum xbtree_key_contig xbtree_key_contig(uint64_t x, uint64_t y)
 enum xfs_btree_type {
 	XFS_BTREE_TYPE_AG,
 	XFS_BTREE_TYPE_INODE,
+	XFS_BTREE_TYPE_MEM,
 };
 
 struct xfs_btree_ops {
@@ -281,6 +282,10 @@ struct xfs_btree_cur
 			struct xfs_buf		*agbp;
 			struct xbtree_afakeroot	*afake;	/* for staging cursor */
 		} bc_ag;
+		struct {
+			struct xfbtree		*xfbtree;
+			struct xfs_perag	*pag;
+		} bc_mem;
 	};
 
 	/* per-format private data */
@@ -455,6 +460,8 @@ xfs_failaddr_t xfs_btree_fsblock_v5hdr_verify(struct xfs_buf *bp,
 		uint64_t owner);
 xfs_failaddr_t xfs_btree_fsblock_verify(struct xfs_buf *bp,
 		unsigned int max_recs);
+xfs_failaddr_t xfs_btree_memblock_verify(struct xfs_buf *bp,
+		unsigned int max_recs);
 
 unsigned int xfs_btree_compute_maxlevels(const unsigned int *limits,
 		unsigned long long records);